A rare image of a clouded leopard on the ground has been captured by a researcher in Indonesia who was trying to photograph slightly less unusual sun bears.

Wai-Ming Wong is working on a doctorate at the University of Kent on how the bears ‑ which are regarded as less critically vulnerable than the leopards, but have received far less attention academically ‑ are surviving in human-dominated landscapes.

His field work is sponsored by Chester zoo, allowing him to spend months in the Sipurak forest, part of the Kercini Seblat national park, a Unesco world heritage site in Sumatra.

Over the last three months he has set up 21 camera traps over a 100sq km stretch of the forest, and as well as images of the small, mainly nocturnal bears he is sending Chester unexpected views of other extremely rare creatures, including Sumatran tigers, marble cats, and Malayan tapirs.

The clouded leopard is classified as "vulnerable to extinction", threatened by hunting for its coat and for traditional medicine, and by the destruction of its native forest habitat across south-east Asia and parts of China.

Wai-Ming Wong's image is exceptionally unusual in showing the leopard on the ground in the wild. The animals spend much of their life high in the trees, their large paws and long tails making them perfectly adapted to balance even on small branches, and flexible enough to run down trunks head first.